I apologise for commenting, I am here for Yemen encounter only, but as per @Mick West suggestion, I shall share what I have found in regards to the cloud line, frustum rotation and horizon. (Mick provided two links to two threads, as @logicbear has reference with illustration to the pods pitch axis, above, and that being central, I replied in this thread and did not comment on the other thread or any other threads, as there are a few. So I respectfully ask that this commentary stays here)

Firstly, Plane bank incorporated into the view.

There is zero dispute that plane bank is reflected in the footage, although I state that it is directly reflected in the footage @ 1:1 (as opposed to the claim,

"Formula "jetPitch = (ObservedCloudAngle - (jetRoll*cos(abs(radians(az)))) / sin(abs(radians(az)))" "

When we remove the plane bank, we are left with a mismatched cloud line still.

Although more easily digestible via @TheCholla post image

I do note that @logicbear has made a representation here,

I am of the opinion that it is parallel to the planes fuselage, not the ground. As the pod is mounted parallel to the planes boresight, the camera would be responsive to the planes pitch, not the ground. So the camera will be tilted an appropriate amount, with maximum tilting occurring at 90 degree azimuth. However, to achieve this, I calculated based on a 3.6 degree pitch for level flight, what the pitch increase would actually be based on bank.

This seems incompatible with some of the earlier assertions (might be a different thread), that pitch could be 6-7 degrees.

So, I then did some simple representations to calculate it myself.

Plane flying straight and level, has a value of 1. When we bank the plane.

At a 30 degree bank, we now have vector sums, with the plane still generating 87 percent of the required lift. So the plane only needs to pitch by 3.6 X 1.13 = 4.07 degrees of pitch to keep level flight. Which is under what the formula came up with "4.1589 degree pitch". So I have high confidence that the pitch values are correct.

Next, I then calculated how much Frustum Roll (essentially how much the camera is tilted) is required with those pitch values,

And de-rotating the footage, removing plane bank @ 1:1 and removing Frustum Roll, this is the result.

Source: https://www.youtube.com/watch?app=desktop&v=PpJ6ppruH70

The end result, demonstrates that the clouds are not the horizon and the footage is more consistent with the F-18, closing in on a close by target, like @Mick West example of a helicopter, getting closer to a balloon. I have my twitter private, but this image should be remembered by everyone as to what happens.

* I will clarify, "Frustum Roll" is NOT the RAW camera Frustum (Pods Eye View), as Mick makes reference to in his Gimbal Analysis video, but the Frustum AFTER the Derotation mirror. This is because the camera will ALWAYS see the image in the correct orientation, its behind the dero, as Mick does state in his Gimbal Analysis video.

Using this, I have stitched the footage together,

And have also worked on what the elevation figures would be, based on the FOV being 0.35 X 0.35.

With the values looking like this (I used 0 as a baseline, so I could use the range to see total changes with respect to the initial angle) and is is the elevation figures look like

So again, as per Micks suggestion, I have placed it into metabunk for discussion.

(I haven't forgotten about Yemen, but I am working on my own version of 3D recreation software, including all of this as it was the catalyst for commenting on "using the cloud line" and had to deep dive this so I could ensure accuracy of my "Marik-rec"(once completed I will give it to him and all copyright to it), and I need it before i can go further on Yemen, AND go fast, gimbal, Omaha etc)

I am also tagging @Kyle Ferriter , @Mendel and @flarkey as I humbly ask for their feedback on the above.

[edited for clarity]